The present invention relates to the surface modification of various carbonaceous materials and compounds. More specifically, the invention provides methods for the incorporation of gamma keto carboxyl containing functional groups onto the surface of carbonaceous materials and compounds and similarly provides several surface modified carbonaceous materials and compounds resulting therefrom.
The surface modification of carbonaceous materials has been widely explored as a means for achieving desired chemical and physical properties not normally exhibited by carbonaceous materials and/or compounds. Recently, there has been a considerable interest in surface modification of carbonaceous materials for improved physicochemical properties in rubber, plastics, coatings and inks.
Traditionally, various additives, dispersants and surfactants were used to improve properties of carbonaceous materials, such as carbon black. However, these materials only provide marginal improvement in the desired properties and such additives can undesirably increase the viscosity of resulting dispersions. Moreover, these additives add significant costs and are therefore economically unfavorable as well. To this end, the concept of surface modification of carbonaceous materials by incorporating specific organic functional groups tends to achieve more desired results. For example, oxidation of carbon black generates surface active hydroxy and carboxylic sites. However, in the past, the concentration of these surface active sites has been very low, thus rendering the method ineffective for improving properties of the carbonaceous materials. As such, existing oxidation methods only provide marginal improvements in desired properties
As an object of the present invention, a method has been developed to chemically bond aliphatic and aromatic carboxylate functional groups to inactive carbon black surface sites with a resulting high level of concentration. These carboxylate functionalities surface bonded thereto advantageously provide for a good interaction with substrates and therefore result in improved properties for use in rubber, plastics, coatings and ink applications.
Among other aspects, the present invention is based upon methods for the preparation of carbonaceous materials comprising a plurality of gamma keto carboxyl containing functional groups surface bonded thereto, and further provides several inventive surface modified carbonaceous materials resulting therefrom.
In a first aspect, the present invention provides a surface modified carbonaceous material, comprising a plurality of gamma keto carboxyl containing functional groups of the general formula xe2x80x94(CO)xe2x80x94CR1R3xe2x80x94CR2R4xe2x80x94(CO)OM surface bonded thereto, wherein R1, R2, R3, and R4 independently or collectively represent hydrogen, hydroxyl, amino, trimethyl amino, sulfonate, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C7 cycloalkyl, C3-C7 cycloalkenyl, heterocycle, carbon-carbon bond, or aryl substituent, which substituents can be substituted or unsubstituted, and wherein M is a hydrogen or a cationic species. Additionally, any one or more combination of R1 and R2, R1 and R4, R3 and R2 or R3 and R4 can collectively represent a carbon-carbon bond, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C7 cycloalkyl, C3-C7 cycloalkenyl, heterocycle, or aryl substituent, which substituent can be substituted or unsubstituted as well.
In a second aspect, the present invention also provides a process for the manufacture of a surface modified carbonaceous material comprising a plurality of gamma-keto-carboxyl containing functional groups surface bonded thereto. Accordingly, the process comprises the steps of introducing a carbonaceous material and an anhydride into a suitable solvent and then reacting the carbonaceous material with the anhydride under conditions effective to provide a surface modified carbonaceous material comprising a plurality of gamma-keto-carboxyl containing functional groups having the general formula xe2x80x94(CO)xe2x80x94CR1R3xe2x80x94CR2R4xe2x80x94(CO)xe2x80x94OH surface bonded thereto, wherein R1, R2, R3, and R4 independently or collectively represent hydrogen, hydroxyl, amino, trimethyl amino, sulfonate, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C7 cycloalkyl, C3-C7 cycloalkenyl, heterocycle, carbon-carbon bond, or aryl substituent, which substituents can be substituted or unsubstituted.
In a third aspect, the invention provides products made from the processes of the invention.
In still a fourth aspect, the present invention further provides an aqueous composition, comprising the surface modified compounds, compositions and materials of the present invention and water.
Additional advantages of the invention will be obvious from the description, or may be learned by practice of the invention. Additional advantages of the invention will also be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. Therefore, it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory of certain embodiments of the invention, and are not restrictive of the invention as claimed.